Conventionally, electrophotographic image-forming apparatuses such as laser printers and LED printers are well-known. Such image-forming apparatuses include developing cartridges. Each developing cartridge includes a developing roller for supplying a developing agent.
According to the conventional image-forming apparatus, a developing cartridge is attachable to a corresponding drum cartridge including a photosensitive drum. When the developing cartridge is attached to the corresponding drum cartridge, a developing roller of the developing cartridge comes into contact with the photosensitive drum. The drum cartridge having the developing cartridge attached thereto is then attached to the image-forming apparatus.